According to the pilot, during a Federal Aviation Administration commercial pilot practical examination, the pilot was asked to execute a simulated engine out emergency procedure, with a 180 degree turn. The pilot reported that when abeam the runway numbers he retarded the throttle to idle and turned to final. He reported that after the landing flare, the examiner told him to lower the nose, but the airplane stalled, and the airplane landed hard. He recalled that the left landing gear collapsed but the left wing did not impact the ground. The airplane exited the left side of the runway and came to a rest in the grass safety area. The pilot reported that he did not recall whether or not the examiner grabbed the flight controls, and he does not recall the examiner telling him to abort the landing and go around. The airplane sustained substantial damage to the left wing. According to the examiner, the pilot was asked to execute a simulated engine out emergency procedure, with a 180 degree turn, and that the pilot's approach was relatively stable. He reported that he told the pilot to keep the nose down after the flare, but the airplane stalled, and landed hard. He conveyed that the events occurred so quickly that he did not have time to grab the controls. He reported that the left main landing gear collapsed, but held enough of a load to prevent the airplane wing from striking the ground. The airplane exited the runway to the left, and came to a stop in the grass safety area without further incident. Both pilots reported that there were not any pre-accident mechanical failures or anomalies with the airplane that would have precluded normal operation prior to the accident.